I have an iPad set up with SideCar. I'm using BetterDisplay to change the orientation of the iPad to portrait mode as macOS doesn't support that natively.

The issue is that when my Macbook Pro goes to sleep with the display enabled, more often than not the orientation is set to landscape when it wakes up again, which means the screen is stretched and in the wrong orientation. See images for examples.

MacBook Pro M3 Max, 36 GB of RAM
macOS 15.4.1
BetterDisplay 3.5.5